FGA04 Datasheet | Thorlabs

Description The Thorlabs FGA04 photodiode is ideal for measuring both pulsed and CW fiber light sources, by converting the optical power to an electrical current. The In Ga As detector is housed in a TO-46(mod) package with an anode, cathode and case connection, mounted in an FC bulkhead connector. The photodiode anode produces a current, which is a function of the incident light power and the wavelength. The responsivity ℜ(λ), can be read from Figure 1 to estimate the amount of photocurrent to expect. This can be converted to a voltage by placing a load resistor (RLOAD) from the photodiode anode to the circuit ground. The output voltage is derived as: Vo = P - ℜ(λ) - RLOAD The bandwidth, f BW, and the rise time response, TR, are determined from the diode capacitance, CJ, and the load resistance, RLOAD, as shown below. The diode capacitance can be lowered by placing a bias voltage from the photodiode cathode to the circuit ground. The effect of the bias voltage vs. Diode capacitance can be read from Figure 2. f BW = 1/(2π - RLOAD - CJ), TR = 0.35/f BW 3154-S01 Rev A 7/21/00 Page 1 of 2 Related Thorlabs Products D400FC, FGA10, Fiber Optic cables and Patch Cords, FC Connectors, and FC fiber polishing kits. Typical Circuit Diagram Noise Filter (Typical Values) R1 1K C1 0.1UF + RLOAD Vo - Typical Plots Responsivity (A/W) 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 800 FGA04 Responsivity Wavelength (nm) Figure 1 Capacitance vs Reverse Bias Capacitance (p F) 0.1 0 1 2 3 4 5 6 7 8 9 10 Reverse Bias Voltage (V) Figure...